Search Results (1,237)

This study evaluated the effects of a strictly auditory–vocal instructional package, combining cued vocal rehearsal, forward chaining, and multiple stimulus control arrangements, on the acquisition of forward intraverbal story recall (RC, divergent relations) and the emergent performance on untaught reverse character identification (CI, convergent relations) probes across nine children with autism spectrum disorder (ASD). Utilizing a concurrent multiple-baseline design across character chains replication, the 1:1 intervention integrated the auditory–vocal components without initial permanent visual aids. All nine participants met the mastery criterion for the directly taught forward story-recall chains (mean = 4.6, 4.9, and 4.3 sessions across target characters). Following instruction, unreinforced probe performance on untaught CI relations increased above pre-instruction levels for all participants, with seven achieving mastery on these convergent tasks. Maintenance probes conducted at 2 and 4 weeks post-instruction demonstrated sustained responding for the majority of participants, though marked individual variability—including notable performance decays in story recall for two participants—was observed. Because a formal component analysis was not conducted, the specific contribution of vocal rehearsal cannot be isolated from the overall package, and theoretical mechanisms such as joint control serve only as a cautious, tentative conceptual account. While limited by CI’s functional problem-solving evidence being tempered by its measurement format within the staggered concurrent arrangement, the absence of component isolation, and direct classroom generalization probes, these preliminary findings suggest that package utilizing strictly auditory–vocal arrangements demonstrates initial feasibility for establishing complex intraverbal forward chains under controlled 1:1 clinical conditions. This foundation allows future research on adapting this package, considering temporal location parameter adjustments, to support multi-component stimulus control for vocal independence within inclusive classroom settings like Learning in Regular Classrooms (LRC). Full article

Historical mining districts are long-term sources of environmental contamination, especially where agriculture and grazing occur near mining areas. This study evaluates mercury (Hg) and other potentially toxic elements (PTEs) in soils from Solana de Peñarrubia, within the Almadén mining district (Spain). Thirty-four soil samples collected using a regular staggered grid were analyzed for total Hg and major oxides and selected trace elements. Spatial patterns were evaluated using Kriging interpolation, hierarchical clustering, PCA, and the geoaccumulation index, after standardizing variables to minimize differences in magnitude among them. Thermal desorption and microscopy were performed on three selected high-Hg samples, with thermal assignments interpreted as operational rather than definitive mineralogical identifications. Hg concentrations ranged from 10 to 994 mg kg⁻¹, with the highest values in the northern sector. The PCA separated cropland soils, associated mainly with lithological variables, from soils with anthropogenic inputs related to Hg, Pb, SO₃, and SiO₂. The geoaccumulation index indicated Hg enrichment, reaching the extremely polluted category at the maximum concentration. Thermal desorption profiles were dominated by fractions within the reference range of α-HgS, accounting for 78.27–87.44% of the estimated relative abundance, while microscopic examination revealed particles consistent with cinnabar in high-Hg samples. The Hg anomaly showed no straightforward relationship with the mapped local lithology and may partly reflect, as a working hypothesis, the possible redistribution of Hg-bearing mineralized materials associated with historical mining or metallurgical activities. Full article

This study examines whether China’s Intelligent Manufacturing Pilot Demonstration Program is associated with changes in Huazheng-rated environmental, social, and governance (ESG) performance among listed manufacturing firms. Using a panel of 2581 firms from 2012 to 2022, we exploit the staggered admission of 91 pilot firms. The preferred doubly robust group-time difference-in-differences estimator yields an average treatment effect of 0.881 Huazheng points, positive at the 10% level. The conventional firm and year fixed-effects estimate is 1.801 points and significant at the 1% level; it is retained as a benchmark rather than the main policy estimate. The direction remains positive across alternative fixed effects, lagged controls, a pre-COVID-19 sample, reweighting, matching, stacked estimation, randomization inference, wild-cluster bootstrap inference, and leave-one-out tests. Under the benchmark specification, the environmental and governance ratings rise significantly, whereas the social estimate is imprecise. The organizational regressions are consistent with possible information verification, managerial incentive, and financing channels, and cross-fitted double machine learning provides a functional-form check. Overall, pilot designation is associated with higher Huazheng-rated ESG performance, with evidence consistent with a possible policy effect. Selective designation and the provider-specific outcome preclude stronger claims about independently verified corporate sustainability. Full article

The transformation of toluene to benzaldehyde via green and sustainable routes is of great significance in the fine chemical industry. However, hard activation of benzylic C(sp³)-H bonds and facile overoxidation of the generated benzaldehyde collectively render the selective oxidation of toluene extremely challenging. In this study, we constructed a core–shell heterostructure photocatalyst, CeO₂@NiFe-LDH, employing molecular oxygen as the oxidant. Under mild conditions of room temperature and visible-light illumination, the catalyst achieves a toluene conversion rate of 1.936 mmol·g⁻¹·h⁻¹ with an excellent benzaldehyde selectivity of 81.0%, and its catalytic performance is significantly superior to that of the individual single-phase materials and the simple physical mixture. Optical and electrochemical measurements confirm enhanced visible-light absorption and utilization, as well as greatly improved separation and migration efficiency of photogenerated charge carriers. Furthermore, the CeO₂@NiFe-LDH heterostructure features staggered band alignment, promoting S-scheme charge transfer across the heterointerface, thereby substantially boosting the redox capacity of the composite catalyst. Consequently, the photogenerated carriers with high reactivity are fully engaged in catalytic reactions, enabling efficient carrier utilization and ultimately leading to a significantly enhanced photocatalytic performance. This study not only demonstrates the outstanding application potential of CeO₂@NiFe-LDH for the visible-light-driven selective oxidation of toluene to benzaldehyde, but also offers a novel strategy for enhancing the photocatalytic performance of LDH-based materials. Full article

The aim of this paper is to investigate the effect of deformation in the tubes and fins of a car engine cooler on heat transfer parameters during the cooling process. Circular finned tubes in a staggered arrangement in a laboratory cooling circuit of a car engine are studied experimentally. In terms of heat transfer performance, a non-deformed cooler is compared with 20%, 40%, and 60% deformed cooler cores when using air cooling by a cooler fan (CF) and a ram-air fan located in front of the cooler (RAF). The temperature parameters of the coolant and the cooler surface and the values of heat transfer rate, heat transfer coefficient, thermal efficiency, efficiency factor, and Nusselt number are evaluated. Deformation of the cooler core decreases the cooler’s heat dissipation capacity. The combination of a deformed cooler and ram-air cooling is ineffective for maintaining the optimum operating temperature of the coolant, especially under slow-speed driving conditions or at higher ambient temperatures. The cooler fan cooling reaches heat transfer coefficients that are 1.2 to 3.2 times higher and average Nusselt numbers that are 28.2% to 58.5% higher compared to ram-air cooling. Maximum deformation of the cooler core causes a 37% and 40% decrease in the heat transfer coefficient compared to the non-deformed cooler. Efficiency factors of 0.6 and 0.5 for CF and RAF cooling at maximum deformation can lead to significant problems with engine overheating. Full article

Amid growing global economic uncertainty, strengthening tourism economic resilience is critical to the economic sustainability of tourism destinations. Using panel data for 288 Chinese prefecture-level cities from 2010 to 2024, this study uses the staggered designation of the National New-Generation Artificial Intelligence Innovation and Development Pilot Zones as a quasi-natural experiment and applies a staggered difference-in-differences (DID) model to examine whether artificial intelligence (AI) development promoted by the pilot-zone initiative enhances tourism economic resilience. Results show that the pilot-zone initiative significantly enhances city-level tourism economic resilience, and this finding remains robust across a series of endogeneity and robustness checks. Mechanism analysis identifies data factor utilization, technological innovation, and industrial structure upgrading as three parallel channels. Moderation analysis shows that the resilience-enhancing effect of the pilot-zone initiative is stronger in cities with more developed digital infrastructure, higher levels of marketization, and greater human resources. Heterogeneity analysis reveals overall regional heterogeneity and a stronger effect in resource-based cities. These findings clarify the mechanisms and boundary conditions linking AI development promoted by the pilot-zone initiative to tourism economic resilience and provide implications for technology-enabled sustainable tourism development. Full article

In offshore wind farm micro-siting, maximizing annual power generation across all wind directions often involves a trade-off among different directional conditions, especially when the primary and secondary wind directions account for most wind energy. To address this issue, this paper proposes a turbine layout strategy combining horizontal and vertical staggering. The objective function maximizes the simplified capital efficiency (power generation per unit capital cost) under the primary and secondary wind directions, for which a layout optimization model is constructed and solved using the Tian Ji’s Horse Racing Algorithm (THRO). A case study on an offshore wind farm validates the proposed approach. Results show that, compared with manual empirical layout and the GA-PSO algorithm, the proposed strategy significantly improves the simplified capital efficiency under the primary and secondary wind directions, while also enhancing overall power generation efficiency across all wind directions. This offers a new technical pathway for offshore wind farm micro-siting. Additionally, the THRO algorithm converges within 30 iterations, outperforming conventional optimization algorithms and demonstrating its effectiveness in solving such optimization problems. Full article

To address the limited cooling range of ventilation in deep, high-temperature development headings and the lack of coordinated design between coil-based cooling and the ventilation system, this study proposes a coupled “twin-forcing–coil” cooling scheme. Building on conventional overlap (forcing–exhausting) ventilation, a rear-mounted second forcing duct is added to the conventional overlap (force–exhaust combined) auxiliary ventilation system, forming a dual-duct forcing, single-exhausting configuration—hereafter termed the “twin-forcing–single-exhausting” (TFSE) system—that provides a booster (relay) air supply to mitigate the along-path attenuation of cooling capacity and the short-circuiting of cold air; an in situ heat-exchange coil wall further provides supplementary cooling where ventilation-based temperature control weakens. Using a development heading at the 790 m level of a metal mine in Yunnan as the engineering background, a three-dimensional numerical model coupling the roadway, ventilation system, and coil wall was established and validated against nine field monitoring points, showing average relative errors of approximately 1% for temperature and 2–3% for humidity, comparable to the measurement uncertainty of the field instrumentation. Because the numerical model does not account for evaporative and condensation phase-change processes, two supplementary development headings with standing water at the face were used for validation; results showed that model error increases with water accumulation and heading length, indicating the model’s applicability is limited to conditions with intact surrounding rock and minimal seepage. Six operating cases were designed with duct placement and coil spacing as variables. Results show that single-duct ventilation cooling decays markedly beyond 30 m from the face, whereas twin-forcing booster (relay) air supply effectively extends the cooling range, reducing the 30–70 m section temperature by 2.7–2.9 K; the second duct should be positioned where the first duct’s cooling capacity begins to attenuate but is not yet depleted. Based on only two spacing configurations tested (10 m and 15 m), coil-staggered spacing showed limited effect on cooling performance under the field conditions examined; this preliminary finding requires validation across a broader range of spacings. Among the chilled-water conditions tested, an inlet temperature of 280.65 K and a flow velocity of 0.5 m/s offered a reasonable trade-off between cooling uniformity and economic efficiency. Under the boundary conditions and equipment parameters of this case, energy consumption estimates further indicate that the cooling effect per unit electricity consumption of twin-forcing ventilation is roughly 6–8 times that of coil-based cooling, primarily due to pumping losses over the ~240 m chilled-water delivery distance. This energy penalty indicates that coil-based cooling is better suited as a localized, short-distance supplementary measure rather than as a means of extending the cooling range over long distances. Full article

Repeated mining of shallow-buried close-distance coal seams can disturb the fractured strata remaining in the goaf of the upper coal seam. Under gully terrain, mining disturbance is coupled with surface-relief effects, which may reactivate the overburden structure and induce dynamic strata-pressure behavior. In particular, when the working face advances across gullies, the change in surface slope alters the spatial distribution of roof load, while lower-seam extraction further disturbs the fractured rock mass formed by upper-seam mining, increasing the risk of severe strata-pressure behavior and support-crushing accidents. Taking the cross-ditch mining of the 2⁻² and 3⁻¹ coal seams in Anshan Coal Mine as the research object, this study integrates field geological investigation, theoretical calculation, physical similarity simulation, and field engineering verification to analyze overburden structural evolution, key-stratum breaking characteristics, and support-load variation under gully terrain. The results show that gully landforms generate obvious nonuniform loading above the working face. During upslope advance, the roof load gradually increases from the goaf side to the solid-coal side, causing tensile stress concentration at the fixed end of the key stratum and accelerating rock-stratum failure. A cantilever rock-beam mechanical model subjected to parabolic nonuniform loading was established, and the maximum breaking interval of the key stratum was calculated as 24.09 m. With increasing gully slope angle, the load gradient intensifies, the rock-beam breaking interval decreases, and the risk of overburden instability increases. Physical similarity simulation indicates that, when the 2⁻² coal seam working face passes through the 45° steep-slope section, the fractured overburden is more likely to form a stepped rock-beam structure, accompanied by slope rotation, stepped surface subsidence, and a sharp increase in support pressure. Under the 30° gentle-slope condition, The lateral confinement effect is stronger, roof movement is more gradual, and support-pressure fluctuation is reduced. During subsequent extraction of the lower 3⁻¹ coal seam, repeated mining disturbance reactivates the overlying goaf structure, and the upper stepped rock beam and lower hinged rock beam couple to form a double composite structure. When the fracture lines of the upper and lower key strata are staggered, the instability load of the upper structure is mainly buffered by caved gangue and interburden strata. The calculated support resistance in the asynchronous breaking stage is 8248.04 kN, which agrees well with the field-measured value of 8273 kN. When the fracture lines tend to coincide and synchronous breaking occurs, the unstable load of the upper key block is transferred downward and superimposed on the structural load of the lower key block, increasing the required support resistance to 15,165.55 kN, far exceeding the rated working resistance of the ZY9200/15/29 hydraulic support. Sensitivity analysis indicates that gully slope angle is the dominant factor affecting support resistance. As the slope angle increases from 30° to 60°, the support resistance increases from 13,228.65 kN to 18,278.43 kN, and the normalized support-resistance index increases from 0.872 to 1.205. Therefore, synchronous breaking of double key strata is the main mechanical cause of sudden support-load increase and support-crushing risk during cross-ditch mining of shallow-buried close-distance coal seams. The results can provide a basis for hydraulic support selection, roof weakening, weighting-interval control, and dynamic strata-pressure prevention under similar conditions. Full article

We exploit the staggered rollout of the Standard Land Reform across Chinese cities as a quasi-natural experiment to examine its impact on enterprise innovation efficiency. Using a sample of A-share listed companies from 2013 to 2020, we find that the reform significantly increases enterprise-level innovation efficiency by approximately 4.86%. This result remains robust across a series of robustness checks. Mechanism analyses reveal that the reform promotes innovation through reducing transaction costs, increasing fiscal subsidies, and strengthening regional intellectual property protection. Heterogeneity analyses show that the effect is more pronounced for enterprises with higher financing constraints, higher human capital, and greater media attention, as well as in more competitive industries and regions with stronger intellectual property protection. Our findings provide enterprise-level causal evidence that improving land allocation efficiency can foster enterprise innovation, offering policy implications for leveraging institutional reforms in land allocation to promote innovation-driven development. Full article

Conventional flux-reversal permanent magnet motors have problems such as excessive torque ripple and rich harmonic content in direct drive applications such as oil exploration, which restrict their application in high-precision scenarios. To address this issue, this paper presents a hybrid excitation topology that integrates double-armature windings, stator Halbach hybrid permanent magnet arrays, rotor-staggered unequal-tooth and rotor-hybrid permanent magnets. Two-dimensional finite element analysis was conducted using ANSYS Maxwell 2023 R1 to evaluate electromagnetic performance under rated steady-state conditions, rated power 300 kW, rated speed 83 rpm, rated voltage 660 V, rated phase current 307 A, and axial core length 200 mm. The simulation results show that the proposed topology has an average output torque of 34.5 kN·m at rated conditions compared with the traditional flux-to-reverse permanent magnet motor of the same size, and the torque ripple rate is reduced from 27.5% to 17.4%, a relative reduction of 36.8%. The results are based only on numerical simulation and have not been verified by physical prototype experiments. Dynamic control strategies, multi-load transient responses and experimental verification will be carried out in subsequent work. Full article

The European Union’s REPowerEU Plan (2022) targets 10 million tonnes of renewable hydrogen imports by 2030, catalyzing an unprecedented cascade of bilateral green hydrogen partnerships with countries across the Middle East and North Africa (MENA) and Sub-Saharan Africa (SSA). Despite the strategic and developmental significance of these partnerships, the literature has treated hydrogen largely as a techno-economic or single-country problem, leaving the diplomatic architecture and equity dimensions of EU–MENA–SSA hydrogen diplomacy under-theorized and unmeasured. This study addresses these gaps by integrating energy-security realism, regime-complex theory, and critical political ecology into a synthetic framework, and by introducing two novel empirical instruments: a hand-coded dataset of 26 in-scope bilateral hydrogen agreements (2020–2024) and a fully specified protocol for a Green Hydrogen Diplomacy Equity Index (GHD-EI). A longitudinal dyad-year panel skeleton (27 EU importers × 36 MENA/SSA exporters, 2015–2026, 11,664 dyad-year cells) has been constructed to host a planned multi-method quantitative sequence, structural gravity PPML, staggered difference-in-differences, synthetic control, exponential random graph models, and causal forests whose execution against fully populated covariates is reserved for a subsequent paper. This paper is accordingly framed as a data descriptor and specified analytical protocol, reporting descriptive and structural findings from the 26 in-scope agreements: a 2022 inflection synchronized with REPowerEU and COP27; importer-side concentration on Germany (34.6% of agreements) and EU-level framework partnerships (34.6%)—two distinct actors jointly accounting for 69.2%—and a small, statistically non-significant difference in mean partnership depth between MENA (n = 18, M = 3.22) and SSA (n = 8, M = 3.25) exporters (Welch t = −0.08, p = 0.94; Cohen’s d = −0.04). The comparison is likely under-powered (power ≈ 0.20–0.44) given the small SSA cell and reported here as a tentative pattern. At this stage, the study contributes a cross-regional agreement dataset, a fully specified equity-indicator protocol, and a theoretical framework for subsequently evaluating whether the green hydrogen transition advances just internationalism or reproduces green-extractivist patterns. Full article

Industrial legacy cities are trapped in carbon lock-in—a self-reinforcing condition where fossil-fuel infrastructure, industrial structures, and institutional inertia collectively resist urban energy transition. Yet whether and how industrial upgrading policies (IUP) can effectively disrupt this lock-in remains unclear. Using panel data from 148 Chinese legacy cities over 2012–2022, we employ a staggered difference-in-differences model combined with policy-text quantification to evaluate the effects of IUP. Results show that IUP significantly raises urban energy transition by 2.52 percentage points, with technology-enabling instruments delivering the strongest leverage among the three policy tool categories. Mechanism analysis uncovers a co-evolutionary mismatch: green technology innovation mediates 42.21% of the total effect, while the mediating pathway through energy consumption structure remains statistically insignificant—evidence that production-side innovation and energy-side infrastructure exhibit systematically divergent adjustment elasticities in response to industrial upgrading policy. Policy effects also differ across city types, with stronger responses in old industrial base, regenerative, and single-type cities. These findings advance carbon lock-in theory by identifying co-evolutionary mismatch as a distinct source of structural friction in urban industrial transitions and provide actionable pathways for aligning urban industrial restructuring with decarbonization goals. Full article

Amphibious assault vehicles serve as core equipment for coastal defense and amphibious operations worldwide, with irreplaceable strategic value. Featuring outstanding comprehensive performance, modern amphibious assault vehicles can maintain stable navigation under Sea States 3–4 and adapt to complex nearshore hydrological environments, emerging as the primary platform for mechanized landing operations of the Marine Corps. Cluster navigation is an inevitable tactical form in the operational application of amphibious assault vehicles. When multiple vehicles sail in formation, the wave-making and water pressure effects induced by individual vehicles generate prominent wave interference drag within the formation, which significantly impacts the overall navigation efficiency and stability. Based on the nearshore combat background of amphibious landing, this paper investigates different formation layouts of amphibious assault vehicle clusters to determine the optimal configuration for group navigation. First, a numerical simulation and a physical experiment are combined; a certain type of amphibious assault vehicle is taken as the prototype for 3D geometric modeling via SOLIDWORKS. Then, adopting the CFD numerical simulation method, with navigation speed and optimal inter-vehicle spacing fixed, variables including formation layout and number of vehicles are controlled to simulate the flow field characteristics and total resistance of different cluster formations in calm water. Meanwhile, 3D printing technology is applied to manufacture scaled-down models for towing tank tests. The experimental results are in good agreement with numerical simulations, revealing the fundamental hydrodynamic laws of formation navigation. Under optimal inter-vehicle spacing, the longitudinal tandem formation achieves the best drag-reduction effect, while the double-column staggered formation (diamond/V formation) can effectively suppress wave interference drag and improve the overall hydrodynamic performance and tactical coordination. The research provides a solid theoretical basis and data support for optimizing formation sailing strategies, enhancing cluster navigation stability and safety, and improving maritime maneuver efficiency. It is also of universal reference value for the tactical deployment of amphibious combat equipment globally. Full article

Clarifying the dynamic mechanism of rock pillar fracture and its rock burst-inducing mechanism is fundamental for the prevention and control of rock burst disasters in steeply inclined extra-thick coal seam groups. In this study, field monitoring, theoretical analysis, and numerical simulation were combined to investigate the rebound vibration behavior and rock burst-inducing mechanism of fractured rock pillars, and corresponding mitigation measures for rock pillar-induced rock bursts were proposed. The results indicate that instantaneous rock pillar fracture induces reciprocating rebound vibration behavior within the coal seam rock pillar, causing the velocity, displacement, and strain energy density of the rock pillar to remain in a persistent fluctuation state. Meanwhile, periodic mutual conversion between strain energy and kinetic energy occurs throughout the vibration process. During any vibration cycle, the rock pillar cannot recover to its initial equilibrium position, resulting in a sharp increase in the loads acting on the floor side of the B3–6 coal seam and a significant decrease in the loads acting on the roof side of the B1–2 coal seam. Consequently, the B3–6 coal seam remains subjected to transient dynamic loading, whereas the B1–2 coal seam experiences transient unloading after rock pillar fracture. This asymmetric transient loading mechanism is identified as the intrinsic reason for the higher rock burst proneness of the B3–6 coal seam. Based on the dynamic response characteristics of the stope coal rock system, staggered-level mining of the B1–2 and B3–6 coal seams and slotting presplitting in the B3 roadway were proposed as mitigation measures for rock pillar-induced rock bursts. When the stagger distance of the working face increases from 25 m to 100 m, the stress drop of the B3–6 coal seam is 22.9%~28.7%. When the slotting depth of the rock pillar increases from 25 m to 80 m, the stress of the B3–6 coal seam decreases by 9.88%~24.1%. These findings provide theoretical support and engineering guidance for rock burst prevention and control in steeply inclined coal seam. Full article